A compound represented by formula (1) or salt thereof which has an inhibitory effect on mPGES-1, and is useful as an active ingredient for a medicinal drug for preventing and/or treating a disease such as inflammation, pain, rheumatism, or the like (X represents a carbonyl group or a sulfonyl group； R1 represents a hydrogen atom, a halogen atom, an alkyl group, an alkanoyl group, a cyano group, or a carboxyl group； R2 represents an alkyl group, a carbocyclic group, or a heterocyclic group； R3 represents a hydrogen atom or 1-3 substituents； R4 and R5 represent a hydrogen atom, a halogen atom, or an alkyl group； and R6 represents an alkyl group or an alkoxy group).
